1. Field of the Invention
The present invention relates to the technical field of agricultural implements or machines, and in particular to implements of the mower or mower-conditioner type, or to machines for treating plant matter, of the tedder or windrower type.
The invention relates to an agricultural implement or machine comprising a working unit articulated to a chassis or to a carrying structure, said unit being articulated using special-purpose means, the design of which optimizes the operation of the implement. Such optimizing is desirable, for example, when the working unit moves along the ground, which may have more or less extensive progressive unevennesses. The ground thus defines a work surface which is either flat or uneven in places, and to which the implement or machine needs to adapt if work of a uniform quality is to be obtained.
The position of the working unit with respect to the chassis has therefore to be modifiable so as to take account of the various configurations of the ground.
2. Discussion of the Background
Producing an implement or machine capable of being moved over a work surface and comprising:
a carrying structure or chassis, PA1 a working unit articulated to said carrying structure or chassis, with a connecting device, which comprises at least one parallelogramm connection which can be automatically converted into any quadrilateral connection, is already known. PA1 placing the working unit in a normal work position; PA1 moving the working unit over a work surface; and PA1 adapting the position of the working unit to suit the unevennesses encountered on the work surface, is also known. PA1 placing the working unit in a normal work position; PA1 moving the working unit over a work surface; PA1 if necessary moving the working unit to obtain additional raising or lowering with respect to the normal work position, PA1 keeping the angular orientation of the working unit with respect to the chassis constant during an additional lowering; PA1 acting on the angular orientation of the working unit starting from a given amount of raising, by pivoting said working unit about a real or virtual pivot axis, transverse to the direction of forward travel, said pivoting allowing obstacles encountered on the work surfaces to be overcome in an optimum way. PA1 a carrying structure or chassis, PA1 a working unit articulated to said carrying structure or chassis, with a connecting device which comprises at least one parallelogram connection which can be automatically converted into any quadrilateral connection, wherein
The use of a method of articulating a working unit to a carrying structure or chassis, especially for an agricultural machine, which includes:
Indeed, document FR-A-2,458 981 discloses an agricultural machine in which use is made of a parallelogram connection for moving a working unit with respect to a chassis. Such movements allow the working unit, for example a cutting mechanism, to be lowered or raised from a normal work position. The working unit can thus adapt to the unevennesses of the ground over which it is moving. The machine described in this document does, however, have the drawback of not taking into consideration the different configurations of the unevennesses. This may give rise to non-optimal adapting of the working unit to suit the ground and therefore to malfunctioning of or damage to the machine.
From another source, document EP-A-0 339 231 describes, in particular, a mower provided with a cutting mechanism, the mowing cutters of which define a working plane.
This cutting mechanism is supported on a support frame or chassis, via a connecting device, so that said working plane can be inclined about an axis transversal to the direction of travel of the mower. The balancing device as described, has a special structure for making the axis transverse to the direction of travel via an instantaneous center of rotation situated beneath the working plane. Such a connecting device makes it possible to make the front of the working plane pivot upward or downward in order to adapt to unevenness of the ground which corresponds respectively to unevenness of the more or less extensive obstacle and hole type.
A device of this kind may nonetheless have major drawbacks. This is because this connecting device still does not allow all types of unevenness to be overcome in an optimum way. Thus, when the machine and therefore a working unit of the cutting mechanism type gradually enters a hole in a downward direction, the working plane inclines in the same downward direction. The cutting mechanism therefore has an angular orientation which is often poorly suited to attacking the somewhat abrupt upwards slope at the other end of the hole. It inappropriately tends to directly attack the ground and dig into it. Damage to its cutters and mechanical stresses which are detrimental to the machine as a whole are therefore obvious and inevitable consequences under these conditions. Another drawback of such a device is associated with a certain lack of stability when moving over uneven ground. This phenomenon is often accentuated with high forward speeds which may lead to premature wear on the various articulations supporting the cutting mechanism.
Document DE-40 07 735 discloses a mower, comprising a carrying structure, a cutting unit articulated to said carrying structure with a connection device. The latter comprises an articulated link system which allows the cutting unit to rotate upwardly and downwardly so as to follow the unevennesses of the work surface.
Each unevenness that is met by the cutting unit, causes its upward or downward rotation, to fit at best with the shape of the said unevenness.
Such an adaptation to the work surface or soil, does not permit to overcome the above mentioned drawbacks.